1. Field of the Invention
The present invention relates generally to electricity generating apparatus, and more particularly to water-powered electricity generating apparatus.
2. General Background
Running water has long been used to power machinery, and more recently to generate electricity. The majority, if not all, of the electricity produced by running water is produced by high efficiency hydro-electric power plants located in dams. Due to ecological, economical, and/or topological factors, there are relatively few sites that are suitable for dam construction. There are, however, numerous rivers which have sufficient current to produce commercial quantities of electricity, if they can be properly tapped.
There have been various proposals in the past to tap the energy available in river current without the use of dams. To the knowledge of the inventor of the present invention, none of these proposals has been successfully put to use to produce energy in commercial quantities.
One such proposal is described in U.S. Pat. No. 848,522, which discloses a water wheel having a vertical hub from which a number of arms radiate outwardly. One set of arms is positioned adjacent an upper end of the hub, and a second set of arms is positioned adjacent a lower end of the hub, each arm of the upper set being connected to an arm of the lower set with a number of vertical rods. The rods support vertically-oriented blades which are rotatably attached thereto adjacent a first end of the blades. The water wheel is submerged in a river, and the current in the river acts upon the blades. On a first side of the wheel, the current causes the blades to align parallel to the flow of the current. On the second side, the blades are forced into contact with the stops, and provide a surface against which the current acts to rotate the wheel. As the wheel turns past the point at which the rod and stop are aligned parallel to the flow of the current, with the rod downstream from the stop, the current acts on the back face of the blade, causing it to swing 180.degree. to a position in which it is free from the stop and is aligned parallel to the current flow. The blade remains aligned parallel to the current flow until the wheel turns such that the stop and the rod are aligned parallel to the flow of the current, with the rod upstream of the stop. At this point, the blade contacts the stop, and the current acts on the blade to turn the wheel. Thus, each blade spends half of the time in contact with the stop, causing the wheel to turn, and half of the time aligned parallel to the direction of flow of the current, presenting little resistance to the turning of the wheel. The wheel, powered by the blades in contact with the stops, and unhindered by the other blades, rotates continuously in one direction.
When it is desired to stop the rotation of the wheel, a ring is lowered. Lowering of the ring causes the stops to move into a position in which they do not contact the blades, so all blades align parallel to the direction of the flow of the current. Since there are then no blades against which the current can act, the wheel stops rotating.
U.S. Pat. No. 950,676 discloses a device for harnessing energy of a river, the device comprising a number of water wheels similar to that disclosed in U.S. Pat. No. 848,522. The devices are aligned in two rows parallel to the direction of flow of the current. Each wheel has a rotating gear adjacent an upper end thereof. There is a rotary shaft adjacent each row of wheels, each shaft having a gear adjacent each wheel in the row adjacent it. Each wheel mechanically communicates with one of the shafts via a rod having a gear on each end thereof. The teeth of the rotating gears face upward, and the gears of the rods are disposed above the gears of the wheels. Since the gears of the rods are disposed above the gears of the wheels, if one needs to remove the wheels to service them, the rods must first be removed.